My battery builds

Batteries, Chargers, and Battery Management Systems.
EbikeAus   100 W

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Re: My battery builds

Post by EbikeAus » Apr 27 2018 5:23pm

999zip999 wrote:
Apr 27 2018 2:51pm
I put an extra set of sense wires on for ez checking and can manually balance thru the sense wires. You could put cells in large parallel group and charge all to one set voltage for all cells befoe building.
Yes I think ill do that with subsequent packs.
I'm considering buying one of these for balance charging as needed. Just run 2 sets of 7s balance wires.

https://rover.ebay.com/rover/0/0/0?mpre ... 2358059119

I'm currently bulk charging with a 900 watt boost module with a 12v LiFePO4 charger on the input

Thanks for your comment
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999zip999   100 GW

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Re: My battery builds

Post by 999zip999 » Apr 28 2018 9:39pm

I have the una-9 without battery nanny. But Now would get this https://www.fpvmodel.com/una9-plus-inte ... _g460.html.

999zip999   100 GW

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Re: My battery builds

Post by 999zip999 » Apr 28 2018 9:43pm

Buy it for me and let me know. I can only use it at 6s or less. For 24s or 20s. Maybe with new batteries in high-power 18650 cells will change things. Hey if I was over on your side of the pond I be sweeping your floor and pick it up the spare sales that drop off the table

999zip999   100 GW

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Re: My battery builds

Post by 999zip999 » Apr 28 2018 9:48pm

Okay I'll blow out my thoughts and remember there's no scientific proof behind my thoughts. Group all same cells Samsung 25 Panasonic PF Panasonic ga excetera excetera. Now the same voltage of like cells put them in large parallel charge them all to save voltage if I 4.1v charge to 4.1v but before you Parallel Group them make sure your parallel groups are of same voltage and then charge the same voltage so all cells are up to same voltage. Do not put a 2.5v with a 4.2 volt cell this is the danger. This is why your buddy was trying to tell you to buy new cells as they all come the factory at what 3.56 3.85 or something the whole box. I wish I bought the una-9 plus + with battery nanny.
Plus charge thru yhe sense wires only No backing the pack.

EbikeAus   100 W

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Re: My battery builds

Post by EbikeAus » Apr 28 2018 11:11pm

999zip999 wrote:
Apr 28 2018 9:39pm
I have the una-9 without battery nanny. But Now would get this https://www.fpvmodel.com/una9-plus-inte ... _g460.html.
That charger looks pretty good. Doesn't look like I could get one here and postage would not make it worthwhile.
Will probably stick withe the isdt. I have another of their chargers and am happy with it
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EbikeAus   100 W

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Re: My battery builds

Post by EbikeAus » Apr 28 2018 11:16pm

999zip999 wrote:
Apr 28 2018 9:48pm
Okay I'll blow out my thoughts and remember there's no scientific proof behind my thoughts. Group all same cells Samsung 25 Panasonic PF Panasonic ga excetera excetera. Now the same voltage of like cells put them in large parallel charge them all to save voltage if I 4.1v charge to 4.1v but before you Parallel Group them make sure your parallel groups are of same voltage and then charge the same voltage so all cells are up to same voltage. Do not put a 2.5v with a 4.2 volt cell this is the danger. This is why your buddy was trying to tell you to buy new cells as they all come the factory at what 3.56 3.85 or something the whole box. I wish I bought the una-9 plus + with battery nanny.
Plus charge thru yhe sense wires only No backing the pack.
I test all my cells by fully charging, then rest them for 2 weeks or so.
If at 2 weeks they are above 4.14v, they get capacity tested at 1 amp per cell, charged to around 3.5v ready to go in a pack.
Due to the large quantity of cells I get I can cherry pick the best for my batteries 8)
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999zip999   100 GW

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Re: My battery builds

Post by 999zip999 » Apr 29 2018 1:19pm

That's good. I think the battery nanny would be great for a used cell battery builder. Or I wish I saw it when I brought the una9 plus +. But now its to much with shipping. Plus my 5yr old A123 20ah 24s pack is always balance after 1182 cycles no bms. And bulk charge. Plus I gone thru a hyperion 1420 two 1220 always balancing at first. That's way the sense wires for ez checking. And you can get a thru the sense wire balance charger like una6 or bc168 stlye. I'm more interested how your pack stays in balance without bms, but you would have to be the human bms . plus I would only do it with a 15ah or bigger pack.

EbikeAus   100 W

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Re: My battery builds

Post by EbikeAus » May 12 2018 1:24am

EbikeAus wrote:
Apr 26 2018 4:19am
I have around 200km on my 30Q pack now.
Thought I'd record some voltages before and after charging.
It has performed better than expected so far and not bad for cells destined for landfill 😎
I may try a few full charges to see if the bms brings the 2 weaker groups closer.
49.7v 58.1v
3.564 4.183
3.575 4.162
3.566 4.174
3.568 4.178
3.569 4.171
3.586 4.177
3.458 4.090
3.565 4.162
3.489 4.094
3.539 4.172
3.572 4.127
3.577 4.186
3.545 4.190
3.500 4.131
Super happy with the 30Q pack overall. Does exactly what I need in terms of distance and power. Obviously more of both are welcome :lol:

The two lower cell groups (7 & 9) are the only thing that could be improved but is it worth it?

This pack cost me about $70 to build so not complaining! Also these are of course recycled cells, so shouldn't expect perfect balance anyway.

I have considered replacing some or all of the cells in the 2 lower groups as they probably have higher resistance or more use than the rest.
The only tool I have for checking cells resistance is the imax b6 and not sure how accurate that will be?

I'm interested to hear your thoughts. Would you guys bother, or just work at getting next packs better?
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Willow   10 kW

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Re: My battery builds

Post by Willow » May 12 2018 7:25pm

balance the pack properly first... then you will be able to determine under-performing cells after a number of cycles. The golden rule is to always balance the pack well before putting it to use.

EbikeAus   100 W

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Re: My battery builds

Post by EbikeAus » May 12 2018 9:24pm

Willow wrote:
May 12 2018 7:25pm
balance the pack properly first... then you will be able to determine under-performing cells after a number of cycles. The golden rule is to always balance the pack well before putting it to use.
Thanks for that.
So I did balance the cells before building the pack after testing them.
These two lower cell groups seem to be where the under-performing cells are.
I should add that I only charge this pack to 57.5. At this voltage the groups are very close apart from the two which are consistently lower.

This brings me back to the question. Would you bother replacing cells for this amount of voltage delta?
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Willow   10 kW

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Re: My battery builds

Post by Willow » May 12 2018 9:27pm

here in lies the problem of building packs from used cells.

EbikeAus   100 W

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Re: My battery builds

Post by EbikeAus » May 12 2018 10:02pm

Willow wrote:
May 12 2018 9:27pm
here in lies the problem of building packs from used cells.
That's ok I'm happy to work with recycled cells, I have large quantities and they are waay to good for landfill :D

I'm not about to spend $100s on a new pack when I can build packs for next to nothing.

I could just leave it as is, it's actually working really well!
I've done around 220 km on this pack so far with no issues.
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May all your batteries be fully charged and perfectly balanced :P

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Willow   10 kW

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Re: My battery builds

Post by Willow » May 12 2018 10:21pm

What I'm saying is that you will struggle to, if ever, be able to keep them in balance.

Great to recycle the cells, but there are inherent issues, which in the worst case may lead to a fire. Hopefully the BMS will work as it should to prevent a cell group getting too high or low by cutting power. Use the packs as they are, flog them till they are spent, and build the next one.

EbikeAus   100 W

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Re: My battery builds

Post by EbikeAus » May 13 2018 2:54am

Willow wrote:
May 12 2018 10:21pm
What I'm saying is that you will struggle to, if ever, be able to keep them in balance.

Great to recycle the cells, but there are inherent issues, which in the worst case may lead to a fire. Hopefully the BMS will work as it should to prevent a cell group getting too high or low by cutting power. Use the packs as they are, flog them till they are spent, and build the next one.
Yes I agree, I don't think I'll achieve perfectly balanced packs.

The next pack I'll use a bluetooth bms but may also add balance wires for balance charging when needed.
The bms will be more for High and Low voltage cutoff and monitoring with the app
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May all your batteries be fully charged and perfectly balanced :P

EbikeAus   100 W

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Re: My battery builds

Post by EbikeAus » May 16 2018 7:02pm

While my 30Q pack is going great I think my OCD is gonna to be too strong to leave the 2 weak cell groups :lol:

First I'll strip back the heat shrink in that area and try charging them up to meet the voltage of rest of pack.
While I'm at it I'll test IR of those cells to see if anything stands out.

If they drop in voltage again I'll punch the lower 8 cells out and replace them with cells from a good looking 6ah tool pack
Stay tuned 😊
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May all your batteries be fully charged and perfectly balanced :P

EbikeAus   100 W

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Re: My battery builds

Post by EbikeAus » May 28 2018 9:59pm

Have done around 260 km on the 30Q pack now.

I cut some 'windows' in the clear heat shrink last night and charged the 2 low cell groups up to meet the rest.

I noticed one of the cells I hadn't soldered the fuse wire to the busbar, so it was just resting on the busbar. This may have been the cause of one of the low groups.

I'll cycle it a few more times and see where voltages are at.
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May all your batteries be fully charged and perfectly balanced :P

Micklemax   1 µW

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Re: Aeg Battery

Post by Micklemax » Jun 04 2018 6:09pm

Hey Guys I've just brougth two Aeg 58v battery packs and I can't get anywhere close to 58v when fully chargered with the Aeg charger measured packs and can only get 51.9 and 52.4v. Out of box voltage was 45v. The date on the box is from 2016. What are ya thoughts about this...
BBS02 on a 2004 Foes FXR Frame
16.4Ah 50v battery 820Whrs
Nuvinci N171 Geared Hub, 38t Front Chainring
Manitou forks, Curnutt XTD shock

EbikeAus   100 W

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Re: Aeg Battery

Post by EbikeAus » Jun 04 2018 9:17pm

Micklemax wrote:
Jun 04 2018 6:09pm
Hey Guys I've just brougth two Aeg 58v battery packs and I can't get anywhere close to 58v when fully chargered with the Aeg charger measured packs and can only get 51.9 and 52.4v. Out of box voltage was 45v. The date on the box is from 2016. What are ya thoughts about this...
I have about 7 of those batteries.
The first 2 I stripped for the cells, which were all as new!
I've kept the rest intact for ebike batts.

I don't have a factory charger but that voltage sounds a bit low for hot off the charger I think.

Were they new when you got them?
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fechter   100 GW

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Re: Aeg Battery

Post by fechter » Jun 04 2018 11:31pm

Micklemax wrote:
Jun 04 2018 6:09pm
Hey Guys I've just brougth two Aeg 58v battery packs and I can't get anywhere close to 58v when fully chargered with the Aeg charger measured packs and can only get 51.9 and 52.4v. Out of box voltage was 45v. The date on the box is from 2016. What are ya thoughts about this...
Maybe the pack is badly out of balance and the BMS is shutting it down early. Time to check the individual cell voltages.
"One test is worth a thousand opinions"

Micklemax   1 µW

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Re: Aeg Battery

Post by Micklemax » Jun 11 2018 7:54pm

Hey Guys I've just brought two Aeg 58v battery packs and I can't get anywhere close to 58v when fully charged with the Aeg charger measured packs and can only get 51.9 and 52.4v. Out of box voltage was 45v. The date on the box is from 2016. What are ya thoughts about this...
[/quote]

I have about 7 of those batteries.
The first 2 I stripped for the cells, which were all as new!
I've kept the rest intact for ebike batts.
I don't have a factory charger but that voltage sounds a bit low for hot off the charger I think.
Were they new when you got them?
They were brand new when I got them got them replaced by Aeg with two more brand new and they charged upto 58.2v these are working as they should be. Nice one Aeg
BBS02 on a 2004 Foes FXR Frame
16.4Ah 50v battery 820Whrs
Nuvinci N171 Geared Hub, 38t Front Chainring
Manitou forks, Curnutt XTD shock

EbikeAus   100 W

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Re: My battery builds

Post by EbikeAus » Aug 04 2018 5:23pm

Quick update on my 30Q pack.

Image

I manually charged the 2 lower cell groups with imax b6 to meet voltage of other groups. After a few more bulk charges they are staying equal.

This pack has exceeded my expectations in every way! Have over 300 km on it now.

The weather is starting to improve here so looking forward to getting out more soon :D
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May all your batteries be fully charged and perfectly balanced :P

EbikeAus   100 W

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Re: My battery builds

Post by EbikeAus » Dec 14 2018 12:37am

Bit of an update on my 14s 4p 30Q pack..I've put 400 km on it now and still going strong. No issues

I have completed my 14s 5p 25R (recycled cells) pack for my Mongoose conversion build.
Changes/ improvements I made on this next pack are :

On this one I added a layer of Kapton tape underneath the clear shrink wrap.
I used a 60 amp Bluetooth BMS, which I'm very happy with so far.
I used 15 amp fuse wire instead of the usual 8 amp.
I have tested this pack with the LR small block and it handles the 50 amps no problems.

I wired this one the same as the last pack so I can interchange them between my two bikes.

If anyone is scared of soldering their first pack I would say go for it, I can see no detriment to the cells so far. I would also highly recommend cell level fuses for added safety.


Image

Image

Image

Image

Image
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999zip999   100 GW

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Re: My battery builds

Post by 999zip999 » Dec 14 2018 4:13pm

Ain't that fun do you have a link that BMS ?

EbikeAus   100 W

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Re: My battery builds

Post by EbikeAus » Dec 14 2018 5:08pm

999zip999 wrote:
Dec 14 2018 4:13pm
Ain't that fun do you have a link that BMS ?
Yep I enjoy it..and save a lot of money. That last pack cost me under $100 to build.

Sure here it is :thumb:

Next time I buy one it will cost less as I won't need to order the PC interface, I already have one now.
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May all your batteries be fully charged and perfectly balanced :P

999zip999   100 GW

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Re: My battery builds

Post by 999zip999 » Dec 15 2018 12:43pm

How about a link for the bms ?

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